Abstract |
The 7S and 11S globulins of peanuts are subjected to proteolysis two days after seed imbibition, with Ara h 1 and the arachin acidic chains being among the first storage proteins to be mobilized. Proteolytic activity was greatest at pH 2.6-3 and is inhibited by pepstatin A, characteristic of an aspartic protease. This activity persists in seedling cotyledons up to at least 8 days after imbibition. In vitro proteolysis of Ara h 1 at pH 2.6 by extracts of cotyledons from seedlings harvested 24 h after seed imbibition generates newly appearing bands on SDS-PAGE. Partial sequences of Ara h 1 that were obtained through LC-MS/MS analysis of in-gel trypsin digests of those bands, combined with information on fragment size, suggest that proteolysis begins in the region that links the two cupin domains to produce two 33/34 kD fragments, each one encompassing an intact cupin domain. The later appearance of two 18 and 10/11 kD fragments can be explained by proteolysis within an exposed site in the cupin domains of each of the 33/34 kD fragments. The same or similar proteolytic activity was observed in developing seeds, but Ara h 1 remains intact through seed maturation. This is partly explained by the observation that acidification of the protein storage vacuoles, demonstrated by vacuolar accumulation of acridine orange that was dissipated by a membrane-permeable base, occurs only after germination. These findings suggest a method for use of the seed aspartic protease in reducing peanut allergy due to Ara h 1.
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Authors | Karl A Wilson, Anna Tan-Wilson |
Journal | Plant physiology and biochemistry : PPB
(Plant Physiol Biochem)
Vol. 96
Pg. 301-10
(Nov 2015)
ISSN: 1873-2690 [Electronic] France |
PMID | 26322854
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
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Copyright | Copyright © 2015 Elsevier Masson SAS. All rights reserved. |
Chemical References |
- Antigens, Plant
- Ara h 1 protein, Arachis hypogaea
- Glycoproteins
- Membrane Proteins
- Plant Proteins
- Aspartic Acid Proteases
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Topics |
- Amino Acid Sequence
- Antigens, Plant
(chemistry, metabolism)
- Arachis
(growth & development, immunology)
- Aspartic Acid Proteases
(metabolism)
- Electrophoresis, Polyacrylamide Gel
- Glycoproteins
(chemistry, metabolism)
- Hydrogen-Ion Concentration
- Membrane Proteins
- Microscopy, Confocal
- Molecular Sequence Data
- Plant Proteins
(chemistry, metabolism)
- Proteolysis
- Sequence Homology, Amino Acid
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